Fatal Metformin Intoxication: A Case Report in a Young Adult with Intellectual Disability

Introduction: Metformin-associated lactic acidosis is a rare but life-threatening complication of a widely prescribed therapy for type 2 diabetes. This case report describes a fatal outcome following intentional metformin intoxication in a vulnerable patient with intellectual disability. Case Presentation: The patient was initially asymptomatic but shortly became unresponsive and died. The cause of death was established as metformin intoxication through postmortem toxicological analysis, which revealed a cardiac blood metformin concentration of 53.60 μg/mL. This finding was supported by the presence of metformin tablet debris in the gastric contents and the exclusion of alternative causes, including traumatic injury and co-ingested sulfonylureas. Conclusion: This case underscores the critical need for early detection of metformin toxicity and highlights the essential role of clinical toxicology in guiding postmortem diagnosis.